docs: def Archimedes(L, rhof, rhop, mu, g=g):
      r'''Calculates Archimedes number, `Ar`, for a fluid and particle with the
      given densities, characteristic length, viscosity, and gravity
      (usually diameter of particle).
  
      .. math::
          Ar = \frac{L^3 \rho_f(\rho_p-\rho_f)g}{\mu^2}
  
      Parameters
      ----------
      L : float
          Characteristic length, typically particle diameter [m]
      rhof : float
          Density of fluid, [kg/m^3]
      rhop : float
          Density of particle, [kg/m^3]
      mu : float
          Viscosity of fluid, [N/m]
      g : float, optional
          Acceleration due to gravity, [m/s^2]
  
      Returns
      -------
      Ar : float
          Archimedes number []
  
      Notes
      -----
      Used in fluid-particle interaction calculations.
  
      .. math::
          Ar = \frac{\text{Gravitational force}}{\text{Viscous force}}
  
      Examples
      --------
      >>> Archimedes(0.002, 2., 3000, 1E-3)
      470.4053872
  
      References
      ----------
      .. [1] Green, Don, and Robert Perry. Perry's Chemical Engineers' Handbook,
         Eighth Edition. McGraw-Hill Professional, 2007.
      .. [2] Cengel, Yunus, and John Cimbala. Fluid Mechanics: Fundamentals and
         Applications. Boston: McGraw Hill Higher Education, 2006.
      '''
      return L**3*rhof*(rhop-rhof)*g/mu**2